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    <meta charset="UTF-8">
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    <title>Document</title>
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<body>
    <script>
        var time = prompt("请输入时间");
        if (time >= 6 & time <= 12) {
            alert("早上好")
        } else if (time >= 13 & time <= 18) {
            alert("下午好")
        }else if (time >= 19 & time <=23){
            alert("晚上好")
        }else if (time >=0&time <= 5){
            alert("现在是休息时间，不要讲话")
        }
    </script>
</body>

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